Safety Performance Indicator (SPI) metrics (Metrics Episode 14)
SPIs help ensure that assumptions in the safety case are valid, that risks are being mitigated as effectively as you thought they would be, and that fault and failure responses are actually working the way you thought they would. Safety Performance Indicators, or SPIs, are safety metrics defined in the Underwriters Laboratories 4600 standard. The 4600 SPI approach covers a number of different ways to approach safety metrics for a self-driving car, divided into several categories. One type of 4600 SPI safety metric is a system-level safety metric. Some of these are lagging metrics such as the number of collisions, injuries and fatalities. But others have some leading metric characteristics because while they’re taken during deployment, they’re intended to predict loss events. Examples of these are incidents for which no loss occurs, sometimes called near misses or near hits, and the number of traffic rule violations. While by definition, neither of these actually results in a loss, it’s